土地利用变化对东北温带幼龄林土壤碳氮磷含量及其化学计量特征的影响  

The effect of land use change on soil carbon,nitrogen,and phosphorus contents and their stoichiometry in temperate sapling stands in northeastern China

作　　者：周正虎[1] 王传宽[1] 张全智[1] 

机构地区：[1]东北林业大学生态研究中心,哈尔滨150040

出　　处：《生态学报》2015年第20期6694-6702,共9页Acta Ecologica Sinica

基　　金：林业公益性行业专项(201104009-05);国家"十二五"科技支撑项目(2011BAD37B01);教育部长江学者和创新团队发展计划(IRT1054)

摘　　要：土地利用方式的改变打破森林生态系统原有的碳氮磷平衡,从而显著地影响森林生态系统的生物地球化学循环过程。以地段相邻、林龄相同(10年生)、原始植被一致但土地利用方式不同(无土壤翻动的天然次生林[NS]、间作大豆而土壤翻动中等的人工林[MS]、间作人参而土壤翻动严重的次生林[SS])的温带幼龄林为对象,探索土地利用变化对土壤碳、氮、磷含量及相互关系的影响。结果显示:(1)土地利用方式显著改变表层和深层土壤碳含量,各土壤层次碳含量均呈现NS>MS>SS;而氮含量仅在0—20 cm具有显著性差异(P<0.05);不同土地利用类型之间磷含量无显著差异(P>0.05);表明碳氮磷对土地利用变化敏感程度不同。(2)SS土壤碳氮比(C/N)和碳磷比(C/P)低于NS和MS,而NS和MS之间C/N和C/P因土壤层次而异。不同土壤层次氮磷比(N/P)均随土壤翻动强度的增加而显著减小(NS>MS>SS,P<0.05),且随土层加深而降低;表明N/P相对于C/N和C/P可能对土地利用变化具有更优生态指示功能。(3)土地利用变化显著改变土壤碳-氮、碳-磷、氮-磷的耦合关系。土壤碳-氮(C-N)之间存在极显著(P<0.001)的线性关系,其中3种土地利用方式的土壤C-N关系的斜率差异不显著(P=0.458,共同斜率为11.1),但截距差异显著(P<0.001)。结合本地区和全球文献数据分析指出,森林土壤碳氮关系既有大尺度上的普适性,又有小尺度上对土地利用方式响应的局域分异性。Anthropogenic land use change alters the equilibrium among soil carbon（ C）,nitrogen（ N）,and phosphorus（ P） in the forest ecosystem,likely affecting the biogeochemical cycles. In this study,conducted in northeastern China,we measured C,N,and P contents along soil profiles in adjacent sapling stands identical in age（ 10 years） and primary vegetation,but differing in land use type. Land use types included naturally regenerated stands without soil disturbance（ NS）,moderately disturbed stands（ two-year interplanting of soybean after artificial reforestation,MS）,and severely disturbed stands（ natural reforestation after planting Panax ginseng for 10 years,SS）. Our objective was to examine the effects of land use change on soil C,N,and P contents and their stoichiometry. Our results showed that：（ 1） Land use change significantly altered both top- and sub-soil C contents,which descended in the order NS MS SS for each soil horizon. However,land use markedly influenced only top-soil N contents and did not significantly influence P content alongthe entire soil profile（ P 〉0. 05）. These results suggest differing sensitivities of elements to land use change.（ 2） The C /N and C / P ratios among the three land use types were lowest for SS and differed between NS and MS depending on the soil horizon. Vertical patterns of C / N and C / P ratios differed among land use types,but N / P ratio was consistently constrained by land use change. N / P ratios descended in the order NS MS SS within each soil horizon and decreased with soil depth（ P 〈0. 05）,suggesting that N/P may be a better ecological indicator of response to land use change than C/N and C/P.（ 3） Land use change significantly affected coupled relationships between C-N,C-P,and N-P. Soil C and N contents were linearly correlated（ P 〈0. 001）,regardless of the land use type,with a common slope of 11. 1 but significantly different intercepts（ P 〈0. 001）. This result,together with the synthesis of published local

关 键 词：土地利用变化 生物地球化学 化学计量 碳氮耦合 

分 类 号：S714[农业科学—林学]